Evaluation of particle removal efficiency in sedimentation tank incorporating bottom grid structure

Abstract

A series of comparative experiments, with and without BGS, were carried out in a 2mx1mx1m tank. Samples used were taken from highway runoff and the BGS tested was in 1.3cmx1.5 cm size. The experimental results indicated that the particle removal efficiencies with the application of BGS were about 6% higher than when tested without the BGS for flow rates ranges from 0.2 l/s to 0.5 l/s. SPLIT was developed in the laboratory to test the effectiveness of the system to retain and treat stormwater particles. A series of experiments were conducted with different inflow rates and particle concentrations. The results showed that SPLIT system was able to remove >80% of the particles (measured as TSS concentration) from the laboratory-simulated stormwater runoff. The particle size analysis also demonstrated that reductions in the d50 of the samples in the laboratory testing from 300 µm (influent) to approximately 50 µm (effluent). Reduction in other pollutants that associate with particles is depending on their concentration association by particle size. The laboratory testing results had proved that SPLIT system was able to retain and remove the particles and pollutants effectively under various inflow rates.